Abstract

The standard genetic code is the nearly universal system for the translation of genes into proteins. The code exhibits two salient structural characteristics: it possesses a distinct organization that makes it extremely robust to errors in replication and translation, and it is highly redundant. The origin of these properties has intrigued researchers since the code was first discovered. One suggestion, which is the subject of this review, is that the code’s organization is the outcome of the coevolution of genes and genetic codes. In 1968, Francis Crick explored the possible implications of coevolution at different stages of code evolution. Although he argues that coevolution was likely to influence the evolution of the code, he concludes that it falls short of explaining the organization of the code we see today. The recent application of mathematical modeling to study the effects of errors on the course of coevolution, suggests a different conclusion. It shows that coevolution readily generates genetic codes that are highly redundant and similar in their error-correcting organization to the standard code. We review this recent work and suggest that further affirmation of the role of coevolution can be attained by investigating the extent to which the outcome of coevolution is robust to other influences that were present during the evolution of the code.

Notes

Acknowledgments

We thanks Marcus W. Feldman, Ilan Eshel, Aaron Hirsh, Dmitri Petrov, Michael Lachmann, Tuvik Becker, Ben Kerr, Jennifer Hughes, Steve Freeland, Rob Knight, Erel Levine, Emile Zuckerkandl, and three anonymous reviewers for valuable comments at various stages of this work. We also thank Tsvi Tlusty for his comments and for sharing his exciting results with us. The research of D.A. and G.S. was partly supported by NIH Grants GM28016 and GM28428 to Marcus W. Feldman. G.S. was also supported by a Koshland Scholarship and by the Center for Complexity Science of the Yashaya Horowitz Association.